Catfish in Shuangyashan

Catfish in Shuangyashan

　　Catfish are nocturnal animals, staying quietly hidden during the day in depressions on the riverbed or under tree roots. They have a large appetite—for example, larger species such as those in the Danube may attack small water birds or mice. Catfish are aggressive bottom-feeders. They are sensitive to light and prefer living in crevices near the riverbanks, deep pits, burrows at the base of tree roots, or rocky caves, as well as in slow-moving waters.

In still waters such as reservoirs, ponds, lakes, and weirs, they often lie hidden in the dark at the bottom or beneath masses of water hyacinth, water lettuce, or water spinach. They become active and start foraging in spring. After winter arrives, they stop eating and hibernate in deep waters or caves. If undisturbed, they generally remain still.

Catfish have small eyes and poor vision. They are most active at night and rely entirely on their sense of smell and two pairs of whiskers to hunt. They are voracious eaters—the hotter the weather, the more they eat, and they are especially active on overcast days and at night. Catfish mature early, typically reaching sexual maturity in their first year. In the Yangtze River region, the spawning season runs from April to June, starting earlier the further south and later the further north. During spawning, they pursue each other in groups. Similar to Darwin’s frog, male catfish also carry the eggs laid by the female in their mouths to incubate the young.

The difference is that males cannot eat during this period. Fry feed on plankton and mollusks, with aquatic insect larvae and shrimp being their delicacies. Catfish are greedy eaters and grow quickly—juveniles weighing around 500 grams will voraciously consume crucian carp, carp, and similar fish. The largest individuals can exceed 40 kilograms.

Catfish thrive in waters with temperatures between 20–25°C. Most catfish lack scales and have slippery skin. They feature flat heads and large mouths, with four whiskers on their upper and lower jaws that help them detect taste.

Catfish are known for having three large features: a large mouth, a large head, and a large belly. Their coloration comes in two types: one is bluish-gray, and the other is yellowish, with the yellowish variety often having spots. Catfish eggs are toxic—if ingested, they can cause vomiting, abdominal pain, diarrhea, difficulty breathing, and in severe cases, paralysis.